Cranial nerve deficits from various pathologic processes of the head and neck may result in characteristic patterns of denervation muscular atrophy. Such atrophic patterns may be clues to the location and extent of the lesion, particularly when cranial nerves are involved early in the course of the disease process. Thirty-six patients with computed tomographic (CT) evidence of muscular atrophy secondary to pathologic conditions involving the motor division of cranial nerves were examined. Five characteristic denervation muscular atrophy patterns seen on CT scans were identified. In several patients, identification of the muscular atrophy pattern was the only clue to the presence of a pathologic condition. Recognition of these atrophic patterns can prevent misinterpretation of their CT appearance and direct the CT examination to the course of the compromised cranial nerve from the brainstem to its peripheral innervation.